diff options
| author | Song Liu <song@kernel.org> | 2025-06-12 22:28:56 -0700 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2025-06-17 08:40:59 -0700 |
| commit | a766cfbbeb3a74397965a8fa2e9a402026d3e1d8 (patch) | |
| tree | 24adc39841dec7916f7ae7ead60c890731e02c35 /kernel | |
| parent | 9afe652958c3ee88f24df1e4a97f298afce89407 (diff) | |
bpf: Mark dentry->d_inode as trusted_or_null
LSM hooks such as security_path_mknod() and security_inode_rename() have
access to newly allocated negative dentry, which has NULL d_inode.
Therefore, it is necessary to do the NULL pointer check for d_inode.
Also add selftests that checks the verifier enforces the NULL pointer
check.
Signed-off-by: Song Liu <song@kernel.org>
Reviewed-by: Matt Bobrowski <mattbobrowski@google.com>
Link: https://lore.kernel.org/r/20250613052857.1992233-1-song@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/bpf/verifier.c | 5 |
1 files changed, 2 insertions, 3 deletions
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index a7d6e0c5928b..169845710c7e 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -7027,8 +7027,7 @@ BTF_TYPE_SAFE_TRUSTED(struct file) { struct inode *f_inode; }; -BTF_TYPE_SAFE_TRUSTED(struct dentry) { - /* no negative dentry-s in places where bpf can see it */ +BTF_TYPE_SAFE_TRUSTED_OR_NULL(struct dentry) { struct inode *d_inode; }; @@ -7066,7 +7065,6 @@ static bool type_is_trusted(struct bpf_verifier_env *env, BTF_TYPE_EMIT(BTF_TYPE_SAFE_TRUSTED(struct bpf_iter__task)); BTF_TYPE_EMIT(BTF_TYPE_SAFE_TRUSTED(struct linux_binprm)); BTF_TYPE_EMIT(BTF_TYPE_SAFE_TRUSTED(struct file)); - BTF_TYPE_EMIT(BTF_TYPE_SAFE_TRUSTED(struct dentry)); return btf_nested_type_is_trusted(&env->log, reg, field_name, btf_id, "__safe_trusted"); } @@ -7076,6 +7074,7 @@ static bool type_is_trusted_or_null(struct bpf_verifier_env *env, const char *field_name, u32 btf_id) { BTF_TYPE_EMIT(BTF_TYPE_SAFE_TRUSTED_OR_NULL(struct socket)); + BTF_TYPE_EMIT(BTF_TYPE_SAFE_TRUSTED_OR_NULL(struct dentry)); return btf_nested_type_is_trusted(&env->log, reg, field_name, btf_id, "__safe_trusted_or_null"); |